Lock and load: Half-Life 2 is about to kick PC game graphics up a notch. The sequel, due this fall, will introduce a new gaming engine and texturing technique developed by Valve Software. The technologies imbue physical attributes - like weight, mass, density, friction, and acoustics - to characters and objects in the first-person shooter.

If you throw a wooden table against a wall, it splinters and breaks, just as it would in the real world. Likewise, deadly force sends bodies flying (top); power lines sway in the wind (center); and water splashes when sprayed with bullets (bottom). For every action, there's a reaction. Watch your back.